This invention relates to puller tools and, more particularly, to power operated puller tools such as hydraulic puller tools.
Power operated puller tools, such as hydraulic puller tools have long been used with a great deal of success in extracting pins or the like from force-fit connections. A typical hydraulic puller tool includes a housing defining an annular chamber with a hollow, open center extending from end to end and a piston mounted within the chamber and having an end extending from the housing with an opening in the end aligned with the hollow center of the housing. In the usual case, the housing is affixedly mounted in spaced relation to the pin to be pulled and a bolt or the like is inserted into the hollow center of the housing through the opening in the piston end such that the head of the bolt abuts the latter. The bolt is threaded into a tapped bore in the pin to be pulled and hydraulic fluid under pressure is admitted into the chamber to extend the piston from the housing, thereby pulling the pin from its bore by reason of the connection of the piston to the pin through the bolt.
Such pulling tools work well for their intended purpose so long as (a) the length of the piston stroke is sufficient to completely free the pin from the bore in which it is force-fit and (b) there is sufficient room in the environment of use to allow sufficient extension of the piston to pull the pin free. When such circumstances do not prevail, however, other measures must be taken. For example, in some cases, where one operation of the puller tool is insufficient to fully free the pin, it may be necessary to disassemble the arrangement and set it up anew using a shorter bolt. In other cases, where sufficient room exists, after one operation of the tool, shims may be disposed between the bolt head and the piston and the tool again operated.
While such procedures will ultimately result in the pin being freed from the bore in which it is received, they are frequently time consuming and, when it is necessary to perform them in relatively inaccessible spaces, extremely difficult and tedious to perform in terms of properly manually locating the parts.